This application claims the benefit of Japanese Application No. 2001-360280 filed Nov. 27, 2001.
The present invention relates to an X-ray generator, or more particularly, to an X-ray generator having a tank, which accommodates a high-voltage assembly and an X-ray tube, has an insulating fluid poured thereinto, and is sealed. In the X-ray generator, the volume expansion of the insulating fluid can be compensated for without the necessity of labor-intensive maintenance.
In an X-ray generator having a tank, which accommodates a high-voltage assembly and an X-ray tube assembly, has an insulating fluid poured thereinto, and is sealed, the volume expansion of the insulating fluid is derived from heat dissipation caused by the high-voltage assembly and X-ray tube assembly. This causes the internal pressure of the tank to rise.
In efforts to prevent the rise in the internal pressure of the tank, conventional X-ray generators have a hole bored in the top of the tank. A sack member of a rubber sack is put into the tank through the hole, and the lip of the opening of the sack is attached to the tank wall around the hole in order to keep the tank watertight.
The sack expands or contracts depending on a difference between the luminal pressure of the sack member and the internal pressure of the tank, whereby the luminal pressure of the sack and the internal pressure of the tank become substantially equal to each other. However, the lumen of the sack member communicates with the ambient space at the opening. Therefore, the internal pressure of the tank remains substantially equal to the pressure in the ambient space irrespective of the volume expansion of the insulating fluid.
As mentioned above, the conventional X-ray generators use the rubber sack to compensate for the volume expansion of the insulating fluid.
However, dust floating in the ambient space is likely to accumulate in the lumen of the sack member of the sack. This necessitates periodical cleaning, or anyhow, poses a problem in that labor-intensive maintenance is required.
Moreover, in the conventional X-ray generators, when electric circuit cards are mounted with the tank between them, a cable linking the electric circuit cards is routed outside the tank and becomes an obstacle.
Therefore, an object of the present invention is to provide an X-ray generator capable of compensating for the volume expansion of an insulating fluid without labor-intensive maintenance. Moreover, a cable linking electric circuit cards mounted with a tank between them can be routed so that it will not be an obstacle.
According to the first aspect of the present invention, there is provided an X-ray generator having a tank, which accommodates a high-voltage assembly and an X-ray tube assembly, has an insulating fluid poured into, and is sealed. A tubular body is included to penetrate through the tank. The lumen of the tubular body opens onto the ambient space at both ends of the tubular body. The tubular body expands or contracts depending on a difference between the luminal pressure thereof and the internal pressure of the tank.
In the X-ray generator in which the first aspect is implemented, the tubular body expands or contracts depending on the difference between the luminal pressure thereof and the internal pressure of the tank. Since the lumen of the tubular body opens onto the ambient space, the internal pressure of the tank remains substantially equal to the pressure in the ambient space. Consequently, the volume expansion of the insulating fluid can be compensated for. Since the lumen of the tubular body opens onto the ambient space at both ends of the tubular body, dust floating in the ambient space hardly accumulates in the lumen of the tubular body. This obviates labor-intensive maintenance. Furthermore, the tubular body penetrates through the tank. Therefore, when the cable linking the electric circuit cards mounted with the tank between them passes through the lumen of the tubular body, it is unnecessary to route the cable outside the tank. In other words, the cable linking the electric circuit cards with the tank between them can be routed so that it will not be an obstacle.
According to the second aspect of the present invention, an X-ray generator having the same components as the foregoing ones is characterized in that the tubular body is made of an oil-proof rubber material.
In the X-ray generator in which the second aspect is implemented, the tubular body is made of an oil-proof material. When an insulating oil is adopted as the insulating fluid, deterioration of the tubular body can be prevented. Moreover, since the tubular body is made of a rubber material, the tubular body can readily expand or contract responsively to a pressure.
According to the third aspect of the present invention, an X-ray generator having the same components as the aforesaid ones is characterized in that the oil-proof rubber material is a nitrile rubber.
In the X-ray generator in which the third aspect is implemented therein, a nitrile rubber (NBR) is adopted as the oil-proof rubber material. Consequently, the tubular body can be manufactured at low cost.
According to the fourth aspect of the present invention, an X-ray generator having the same components as the aforesaid ones is characterized in that the tubular body penetrates through the tank in a direction of X-irradiation.
In the X-ray generator in which the fourth aspect is implemented, the tubular body penetrates through the tank in the direction of X-irradiation. The direction of X-irradiation is often a vertical direction close to a horizontal direction. Even if dust floating in the ambient space enters the lumen of the tubular body, the dust drops through the lower opening of the tubular body but does not accumulate.
According to the fifth aspect of the present invention, an X-ray generator having the same components as the aforesaid ones is characterized in that the lumen of the tubular body serves as a passage for the cable linking the electric circuit cards mounted with the tubular body between them.
In the X-ray generator in which the fifth aspect is implemented, the cable linking the electric circuit cards passes through the lumen of the tubular body. This obviates the routing of the cable outside the tank. Consequently, the cable can be routed so that it will not be an obstacle.
According to the sixth aspect of the present invention, an X-ray generator having the same components as the aforesaid ones is characterized in that the electric circuit boards are mounted on an X-ray shooting window side of the tank and on an opposite side thereof. The lumen of the tubular body serves as a passage for the cable linking the electric circuit cards mounted with the tank between them.
In the X-ray generator in which the sixth aspect is implemented, the cable linking the electric circuit cards mounted with the tank between them passes through the lumen of the tubular body. This obviates the routing of the cable outside the tank. Consequently, the cable linking the electric circuit cards mounted with the tank between them can be routed so that it will not be an obstacle.
According to the seventh aspect of the present invention, an X-ray generator having the same components as the aforesaid ones is characterized in that the tubular body has a lip at both ends thereof. When the lips are pressed with attachment plates, the tubular body is locked in the tank and the tank is sealed.
According to the eighth aspect of the present invention, an X-ray generator having the same components as the aforesaid ones is characterized in that the sectional outline of the tubular body is oblong.
In the X-ray generator in which the eighth aspect is implemented, since the sectional outline of the tubular body is oblong, the tubular body can be readily locked in the tank so that the tank will be kept airtight. Moreover, the tubular body readily expands or contracts responsively to a difference in pressure. Moreover, the cable can be readily passed through the lumen of the tubular body.
According to the X-ray generator in which the present invention is implemented, the volume expansion of the insulating fluid derived from heat dissipation caused by the high-voltage assembly and X-ray tube assembly can be compensated for with the expansion or contraction of the tubular body. Moreover, since dust hardly accumulates in the lumen of the tubular body, labor-intensive maintenance is unnecessary. Furthermore, since the cable can be passed through the lumen of the tubular body, the cable will not be routed outside the tank. Consequently, the cable will not be an obstacle, and the neat appearance improves.
Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.